Demonstration of Fluorescent Magnetic Particles for Linking Sources to Sediments at DoD Sites
ER-201214
Objective
This project will demonstrate a particle tracking technology to quantitatively track and map the depositional footprint of particles released from typical Department of Defense (DoD) discharges into adjacent aquatic environments. Magnetic fluorescent particles will be released from specific sources and tracked through the water column and collected at the sediment surface to determine their depositional pattern and quantitatively demonstrate where these particle sources are most likely to impact the sediments. Demonstration and validation will show the utility of this technology to map the distribution of particles, and therefore any sorbed contaminants, from specific sources so potential remedial efforts can focus on the appropriate source of particular contaminants. This is important to DoD and the Environmental Protection Agency (EPA) in complex industrial settings with multiple discharges in close proximity. Performance objectives will focus on matching the physical characteristics of the tracer to the native particles being investigated, validating collection methods, and tracking the mass of tracer particles deposited to the sediments as well as tracking the dispersion of particles that are potentially transported outside the immediate area of concern. The overall performance will also include a relative mass balance to predict how much of the particles and therefore sorbed contaminants remain within the area of concern and how much are transported off site during two typical discharge scenarios that include storm water runoff and a dry dock flooding/deflooding evolution.
Technology Description
Source control, i.e., the reduction of contamination from upstream point or diffuse sources, is a critical element in any management plan for contaminated waterways. In order to understand more of the issues surrounding source control, it is essential to have some understanding of contaminant sources and transport pathways of contaminated particulates. Particle tracking offers a practical means to map the transport pathways of contaminated sediments both at the point of delivery into waterways and following delivery through time and across space. The Partrac (particle tracking) technology uses proprietary tracers called “dual signature” tracers, meaning each tracer grain has two signatures that are used to identify the particle unequivocally following introduction into the environment. The two signatures used are fluorescent color and paramagnetic character. The paramagnetic character gives each particle a magnetic attribute; it will adhere to any permanent or electromagnet if it comes in close proximity. This means submerged magnets (e.g., on bed frames or mooring strings) can be used to intercept the tracer in situ, which is especially useful for showing the tracer in suspension. Use of more than one fluorescent color can be used to label multiple sources. The innovative aspect of this project will show how fluorescent magnetic particles improve the sampling and measuring of tracer particles relative to standard practices, and how this can be used to delineate contaminated sediment transport pathways and indicate connectivity between sources and sinks. The majority of historic studies have been directed towards understanding the transport pathways of sand-size sediments. However, many metal and organic contaminants are bound to surfaces of finer, silt- (and clay) size particles (< 63 μm), and it is these particles that are of interest from a regulatory and ecosystem health standpoint. Partrac (using technology development funding) has advanced the application of the methodology for this silt-size fraction, and this demonstration would provide an innovative case study for its applications with contaminated silt particles.
Benefits
This effort will provide an innovative and cost-effective methodology for tracking sediment particles (and associated sediment contaminants) to specific sources and dischargers in water bodies affected by DoD activities. This methodology is based on demonstrated scientific procedures and will support the correct assignation of regulatory enforcement to DoD and other users, resulting in appropriate cost distributions for compliance and restoration. In 2004, SERDP and ESTCP convened an expert panel workshop and identified high priority DoD needs with respect to sediment contamination. One need was to develop tools to “identify contaminant sources” to “improve long term monitoring efforts.” This project has potentially far reaching benefits for DoD by directly linking sediment contamination to particular sources, thereby allowing any upstream corrective actions and downstream remedial costs to be applied to the correct potential responsible party. (Anticipated Project Completion - 2015)
Points of Contact
Principal Investigator
Dr. James Leather
SPAWAR Systems Center
Phone: 619-553-6240
Fax: 619-553-6305
Document Types
- Fact Sheet - Brief project summary with links to related documents and points of contact.
- Final Report - Comprehensive report for every completed SERDP and ESTCP project that contains all technical results.
- Cost & Performance Report - Overview of ESTCP demonstration activities, results, and conclusions, standardized to facilitate implementation decisions.
- Technical Report - Additional interim reports, laboratory reports, demonstration reports, and technology survey reports.
- Guidance - Instructional information on technical topics such as protocols and user’s guides.
- Workshop Report - Summary of workshop discussion and findings.
- Multimedia - On demand videos, animations, and webcasts highlighting featured initiatives or technologies.
- Model/Software - Computer programs and applications available for download.
- Database - Digitally organized collection of data available to search and access.